#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <algorithm>
#include <sstream>
#include <iostream>
#include <string>
#include <cstdio>
#include <cmath>

using namespace std;

int main() {

	long long N, sum=0, tmp, v;
	cin >> N;
	for (int i=0; i < N; i++) {
		cin >> tmp;
		sum += tmp;
	}
	cin >> v;
	cout <<sum - v << endl;
	return 0;
}